This application relates generally to protecting a data disc from degradation and more particularly to a protector apparatus and method for preventing damage to a data disc stored in a storage case.
Data discs, such as compact discs (“CDs”) and digital vided discs (“DVDs”), typically have large amounts of digitally stored information (data) that is optically readable via a laser mounted on a movable head during rotation of the disc. Data discs are made from laminated layers of plastic. The information is arranged in one or more data layers on circular tracks that can be accessed by the laser through a transparent back layer of the disc. Multiple data layers may be separated by interspersing layers. In addition, discs are typically covered by a protective top layer of the disc that can have labeling applied thereto such as by silkscreening, thermal printing or ink jet printing.
Protective storage cases are typically used to store and protect the data discs. Prior art storage cases typically comprise a top cover or door side, and a back cover or disc side. Each cover is pivotably coupled to a central spine portion to form what is referred to as a “living hinge.” The living hinge allows the covers to pivot toward each other to close the case and encapsulate the disc. The storage cases are typically made of polypropylene, vinyl, or some other plastic for durability. There are many examples of such storage cases in the art.
The discs are typically held in the storage case via a hub on the disc side designed to penetrate a central hole in the disc. The hub is typically equipped with a retaining mechanism that holds the disc within a disc-shaped recess, sometimes referred- to as a disc retention surface, in the storage case.
Data discs may be easily damaged in a number of ways. For example, the bottom of transparent surface of the discs may be scratched rendering the discs unusable. Another common form of damage occurs when the laminated layers of the discs become separated. The separation may be due to repeated thermal stress or can be the result of repeated flexing of the discs. It should be noted, that recordable disks such as CD-Rs, CD-RWs, and DVD-Rs, are more susceptible to the delamination than read-only discs because of their method of construction.
Another, less well known, source of damage to data discs occurs due to long term degradation of the discs while in storage. As discussed above, most data discs are stored in storage cases. It has been determined that long term storage of data discs in storage cases such as those described above actually accelerates the degradation of the data discs over the long term in several ways.
First, the bottom layer of the data disc may be “clouded” by long term storage in a plastic storage case. Plastics, as is well known, “off gas” or emit various hydrocarbons and petroleum-based gases over time as part of their curing and degradation process. When exposed to heat, the off-gassing problem is exacerbated. It has been found that these hydrocarbon gases can cloud the bottom transparent layer (the “data surface”) of the disc. The clouding may be due to physical deposition of the gas on the data surface. In addition, the gases may also react with the plastic of the disc to cause chemical clouding. The clouding reduces the transparency of the transparent layer of the data surface of the disc and therefore inhibits the ability of laser to read the data stored within the disc, ultimately rendering the disc unreadable. Long term storage, especially if coupled with exposure to heat also may cause the storage case material to bond with or otherwise physically attach to any portion of the disc that is in contact with the case, further damaging the disc.
Discs may also be damaged by repeated removal and replacement of the discs from the cases. Many users typically bend data discs when removing them from storage cases or replacing them. This occurs because often when the restraining mechanism of the hub is pressed to release the disc, it does not effectively eject the disc from the case. The user is then forced to attempt to grasp an edge of the disc and lift it from the case. Often this will result in a slight flexing of the disc which, over time, can lead to the separation of laminated layers as well as scratches to the bottom surface. In addition, in most cases it is nearly impossible for users to remove a disc from the case without forcing at least some portion of the disc surface (typically the data surface) to contact the case. This leads to an accumulation of scratches on the data surface over time.
Yet another drawback of a typical storage cases is that the retention device in the hub often does not hold the disc firmly so that the disc does not rattle or vibrate within the case. This can occur for several reasons, and is often due to damaged retention devices caused by users improperly removing or replacing a disc. Loose discs will rattle and impact against the case when exposed to vibration.
Even with these drawbacks, storage cases have become extremely popular. However, as data discs are relatively new, most consumers are unaware that the storage cases will damage discs stored in them over the long term. Now that the problem has been identified, there is a need for a way to protect data discs that are to be stored for a long period of time in typical storage cases. The present invention provides a solution to this and other problems, and offers other advantages over the prior art.